// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_PUBLIC_BROWSER_SCREEN_ORIENTATION_PROVIDER_H_
#define CONTENT_PUBLIC_BROWSER_SCREEN_ORIENTATION_PROVIDER_H_

#include <memory>

#include "base/callback.h"
#include "base/macros.h"
#include "content/common/content_export.h"
#include "content/public/browser/web_contents_observer.h"
#include "device/screen_orientation/public/interfaces/screen_orientation_lock_types.mojom.h"
#include "third_party/WebKit/public/platform/modules/screen_orientation/WebScreenOrientationLockType.h"

namespace content {

class ScreenOrientationDelegate;
class WebContents;

using LockOrientationCallback = base::Callback<void(device::mojom::ScreenOrientationLockResult)>;

// Handles screen orientation lock/unlock. Platforms which wish to provide
// custom implementations can provide a factory for ScreenOrientationDelegate.
class CONTENT_EXPORT ScreenOrientationProvider : public WebContentsObserver {
public:
    ScreenOrientationProvider(WebContents* web_contents);

    ~ScreenOrientationProvider() override;

    // Lock the screen orientation to |orientation|, |callback| is the callback
    // that should be invoked when this request receives a result.
    void LockOrientation(blink::WebScreenOrientationLockType orientation,
        const LockOrientationCallback& callback);

    // Unlock the screen orientation.
    void UnlockOrientation();

    // Inform about a screen orientation update. It is called to let the provider
    // know if a lock has been resolved.
    void OnOrientationChange();

    // Provide a delegate which creates delegates for platform implementations.
    // The delegate is not owned by ScreenOrientationProvider.
    static void SetDelegate(ScreenOrientationDelegate* delegate_);

    // WebContentsObserver
    void DidToggleFullscreenModeForTab(bool entered_fullscreen,
        bool will_cause_resize) override;

private:
    // Calls on |on_result_callback_| with |result|, followed by resetting
    // |on_result_callback_| and |pending_lock_orientation_|.
    void NotifyLockResult(device::mojom::ScreenOrientationLockResult result);

    // Returns the lock type that should be associated with 'natural' lock.
    // Returns WebScreenOrientationLockDefault if the natural lock type can't be
    // found.
    blink::WebScreenOrientationLockType GetNaturalLockType() const;

    // Whether the passed |lock| matches the current orientation. In other words,
    // whether the orientation will need to change to match the |lock|.
    bool LockMatchesCurrentOrientation(blink::WebScreenOrientationLockType lock);

    // Not owned, responsible for platform implementations.
    static ScreenOrientationDelegate* delegate_;

    // Whether the ScreenOrientationProvider currently has a lock applied.
    bool lock_applied_;

    // Locks that require orientation changes are not completed until
    // OnOrientationChange.

    base::Optional<blink::WebScreenOrientationLockType> pending_lock_orientation_;

    LockOrientationCallback on_result_callback_;

    DISALLOW_COPY_AND_ASSIGN(ScreenOrientationProvider);
};

} // namespace content

#endif // CONTENT_PUBLIC_BROWSER_SCREEN_ORIENTATION_PROVIDER_H_
